Abstract
Post-capillary pulmonary hypertension (PH) is a life-threatening complication in dogs with myxomatous mitral valve disease (MMVD). An increase in pulmonary vascular resistance (PVR) is associated with post-capillary PH progression. In humans, PVR estimated by echocardiography (PVRecho) enables the non-invasive assessment of PVR in patients with PH. This study aimed to evaluate the clinical utility of PVRecho in dogs with MMVD, PH probability, and right-sided congestive heart failure (R-CHF). Dogs with MMVD and detectable tricuspid valve regurgitation were included in the study. Dogs were classified into three PH probability groups (low/intermediate/high) and according to the presence or absence of R-CHF. All dogs underwent echocardiographic measurements for right ventricular (RV) morphology and function. PVRecho was calculated by two methods using tricuspid valve regurgitation velocity and velocity–time integral of the pulmonary artery flow (PVRecho and PVRecho2). RV size indicators were significantly higher with a higher probability of PH. RV strain and velocity–time integral of the pulmonary artery flow in the high probability group were significantly lower than those in the other groups. Tricuspid valve regurgitation velocity, PVRecho, and PVRecho2 were significantly higher with an increase in PH probability. Logistic regression analysis revealed a significant association between the presence of R-CHF and increased PVRecho2 and end-diastolic RV internal dimension normalized by body weight. PVRecho and PVRecho2 showed significant differences among the PH probability groups. These non-invasive variables may be useful for the diagnosis and stratification of PH and the determination of the presence of R-CHF in dogs with MMVD.
Highlights
Pulmonary hypertension (PH) is a life-threatening disease in dogs and is characterized by an increase in pulmonary arterial pressure (PAP) and/or pulmonary vascular resistance (PVR) [1, 2]
Our results suggest that PVR estimated by echocardiography may provide additional information for the diagnosis and stratification of PH in dogs with myxomatous mitral valve disease (MMVD), reflecting the increase in PVR and associated right ventricular (RV) adaptation and/or the progression to combined post- and precapillary PH (Cpc-PH)
Those in the high probability group showed substantially higher values compared to those in the low and intermediate probability groups. These results suggest that dogs with high PH probability might have an increase in PVR in addition to the increase in PAP
Summary
Pulmonary hypertension (PH) is a life-threatening disease in dogs and is characterized by an increase in pulmonary arterial pressure (PAP) and/or pulmonary vascular resistance (PVR) [1, 2]. PH secondary to left heart disease is called post-capillary PH because the main factor of increasing PAP is considered to be the increased pulmonary venous pressure; it is classified into two subtypes: isolated post-capillary PH (Ipc-PH) and combined post- and precapillary PH (Cpc-PH) [1, 3,4,5]. The former is caused solely by pulmonary venous congestion due to increasing left atrial pressure, whereas the latter is caused by the increase in PVR associated with pulmonary vascular remodeling in addition to the pathophysiology of Ipc-PH. PVR assessment is essential to determine the pathophysiology and prognosis of dogs with post-capillary PH
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